Burglar-proof lock.



I. L. BRIDGES.

BURGLAR PROOF LOCK.

APBLIOATION FILED APR. 10, 1909.

943,647. PatentedDec. 21, 1909.

2 SHEETS-SHEET 1.

w nm llHllW m I. L. BRIDGES.

. BURGLAR PROOF LOOK.

APPLICATION FILED APR. 10, 1909.

Patented Dec. 21, 1909;

2 SHEETS-SHEET 2:

UNITED STATES PATENT ()FFIQE.

ISAAC L. BRIDGES, OF POWERSVILLE, MISSOURI.

BUIRGLAR-PROOF LOCK.

To all whom it may concern:

Be it known that I, ISAAC L. BRIncEs, a citizen of the United States,residing at Powersville, in the county of Putnam and State of Missouri,have invented a new and useful Improvement in Burglar- Proof Locks, ofwhich the following is a specification.

This invention relates to a safety device adapted to be applied to looksof bank, vault or safe doors, and is also capable of use in connectionwith doors of warehouses, stores and other buildings.

The object of the invention is to prevent tampering with a look bycausing an electric current of considerable strength to pass through thelock or some portion of its mechanism upon the occurrence of a eventduring time.

In the form shown by me I have arranged a device by which an electriccurrent is caused to pass through a door knob, which knob may be one ofthe ordinary exterior door types, or it may be the rotatable knob ordial handle found in connection with combination safe locks. The passageof this current is dependent upon the completing of a normally opencircuit, and in order to com plete the circuit I place a hinged doorstep in advance of the door to be protected and upon which any oneattempting to open the lock must stand the weight of said person forcingthe step downwardly a sufficient dis tance to close an electric circuit.In order however to permit the ready opening of the door by the properparties I arrange an alarm clock mechanism which when operated at thetime set intcrposes an obstacle to the completing of such circuit,thereby providing a device by means of which an electric circuit iscompleted through the lock mechanism or through some part of it during acertain time as for example from the close of business for one day untila certain hour the next morning. To further safe-guard the door I alsoshow means for dividing the circuit so that a portion of the currentwould pass through a key if inserted a predetermined period of in thelock at a time when downward move ment of said hinged step wouldcomplete the circuit.

In the accompanying drawings, Figure 1 is an inside elevation, certainwiring being shown in diagram, illustrating the application of theinvention to a door. Fig. 2 is a Specification of Letters Patent.

Application filed. April 10, 1909.

particular Patented Dec. 21, 1909.. Serial No. 489,195.

vided with a lock casing 2, knob 3 and upon opposite sides of thekeyhole plates 4 which are insulated from the lock casing 2, and whichare contact plates spaced from each other by the keyhole, a circuitbeing established between said plates upon the insertion of a key,provided other portions of the circuit have also been closed. Upon theinside of the door is secured by means of suitable brackets, or in anyother way, a fixed bar 5 which projects upon the inner face of the dooron one side. This bar has its projecting end portion widened and isprovided with a vertical bore 6. Upon one side of the door is placed anelectric switch consisting of a pivoted lever 7 and a curved contactplate 8, over which the lever can be moved. The lever T which isnormally out of contact with the plate 8 has pivoted to it a do pendingrod 9 normally held in raised position by a spring 10. The lower end ofthis rod is in alinement with the wall opening 11 through which extendsa lever 12, the outer end of said lever being secured to a hinged step13, said step being of such a width that it will be necessary for aperson to stand thereon while manipulating the look. A pivoted lever 14is provided at its free end with a hooked member 15 which engages thevertical bore 6 of the bar 5, and this lever is also loosely connectedto the rod 9. A collar 16 isfixed upon the rod 9 and a bolt 17 slides ina guide way 18 which is connected by means of a cord 19 to the windingstem 20 of an alarm clock 21. The electric circuits may be run in manydiiferent ways but for convenience of illustration I have showndiagrammatically line wires A and B from which run, respectively, a wireG to the switch lever 7 and a wire D to a suitable socket E from whichwires F and G run respectively to the door knob and to one of thecontact plates 4. From the knob 3 and the other contact plate -1 wires Hand H lead to a copper contact plate J carried by the door and whichwhen the door is closed makes contact with a plate J from which a wire Kleads to the curved contact plate 8. It will be obvious that there is nocurrent through any of these wires other than the two line wires unlessthe step is depressed, and the depression of this step will cause thelever 12 to draw down the rod 9 which will bring the hook 15 intoengagement with the bar 5 and will draw the switch 7 into engagementwith the plate 8. This will complete a circuit from line wire A throughwires C, K, J and J, H, the knob 3, wire F, socket E, and wire D. toline wire B. If a key is inserted in the keyhole of the door a circuitwill also be completed through wires H and G. It will therefore beobvious that afterthe completing of this circuit any one placing hishands upon the knob 3, which is of metal, or any one inserting a key inthe said keyhole will receive a shock, which may be strong enough toentirely disable the person endeavoring to tamper with the lock. Inorder however to enable proper persons to unfasten the lock or open thedoor the time clock 21 is set, and if set for 8 a. m., the rotation ofthe winding stem 20 will wind the cord 19 and draw the bolt 17 under thecollar 16 thus preventing downward movement of the step, or the drawingdown of the rod 9, the circuit remaining broken at the switch. Also inorder that the parts may be returned to their normal positions afterhaving been depressed the spring 10 is connected at one end to thewalland at the other end to the rod 9, and craws the rod and step totheir positions.

hat I claim is 1. The combination with a lock, oi an electric circuitnormally open and including the look, a movable step, means operated bymovement of the step for closing the circuit, a bolt for locking thecircuit closing means in an inoperative position, means for actuatingsaid bolt at a predetermined time, and means for returning the partsoperated by the step to their normal positions.

2. The combination with a lock, an eleceaaem tric circuit including anaccessible portion of said lock, said circuit being normally open, aswitch for closing said circuit, a movable door step operated by theweight of a person standing thereon, means connecting said switch andsaid door step for moving the switch into closed position, a spring forreturning the parts to their normal positions when the step is relievedof its extra weight, a slidable bolt for holding said movable parts intheir normal position, and means including the winding stem of an alarmclock for drawing said slidable bolt into operative position.

3. The combination with a door having a lock, and a metal knob, anelectric circuit including said knob, said circuit being normallybroken, a bar carried by the door and having a projecting perforated endportion, a pivoted hook lever for engaging said end portion, a switchfor closing the electric circuit, a downwardly movable door step, a rodpivoted to the switch and connected to the door step, said rod beingmovable down ward upon depression of the step, said rod being pivotallyconnected to the hook lever, downward movement of the rod throwing saidlever into engagement with the perforate bar, and a spring secured to afixed support at one end and at the other end to said rod and drawingthe same upwardly after depression of the door step.

l. The combination with a door having a lock, an electric circuitincluding the exterior portion of said lock, a pivoted switch forclosing said circuit, the circuit being normally open, a movable doorstep, a rod connected at one end to the door step and at the other endto the switch, the rod being drawn downwardly upon depression ot thestep, a collar fixed upon the rod, a bolt slidable beneath said collar,an alarm clock having a winding stem, and a cord connected at one end tosaid stem and winding thereupon and at the other end to said bolt.

hlS ISAAC L. X BRIDGES.

mark lVitnesses HLLIAM F. Lnwis J OHN MILLS.

